Component In Total Knee Replacement Research Articles

Processing of Reduced Graphene Oxide Reinforced Ultra High Molecular Weight Polyethylene for Orthopedic Implants

Ultra-high molecular weight polyethylene (UHMWPE) has been used as a bearing material in total joint replacements due to its excellent mechanical properties and biocompatibility. The acetabular cup in total hip replacement and the tibial component in total knee replacement is widely fabricated from UHMWPE. The use of UHMWPE in total joint replacements is well established, and the goal is to improve its mechanical properties, wear resistance, and oxidation resistance. The quality and life span of the artificial joints can be further increased by enhancing the relevant mechanical properties of UHMWPE. The addition of filler material to UHMWPE is an effective way to enhance its relevant properties. In this study, relevant properties of UHMWPE were enhanced by incorporating an appropriate filler. Reduced Graphene Oxide (rGO) was selected as a filler material as it improves mechanical properties, wear resistance, toughness, and thermal stability. Graphene oxide (GO) was synthesized by Modified Hummer’s Method (MHM), and it was thermally reduced to obtain rGO. The synthesized GO was characterized by Fourier Transform Infrared spectroscopy (FTIR) and X-Ray Diffraction (XRD) which confirmed the accurate synthesis. The reduction of GO was validated by the disappearance of (OH) broad peak in the FTIR analysis. The rGO/UHMWPE nanocomposite was prepared by adding 0.7 wt.% of rGO employing the solvent mixing method. The morphology of the composite was validated by Scanning Electron Microscopy (SEM). Tensile and Izod Impact tests were performed on the samples which showed an increase in tensile strength of 33.2% and the impact strength increased by 140.5%. The rGO/UHMWPE nanocomposite with greater tensile and impact strength is an excellent candidate to produce orthopedic implants with superior properties.

A study on Analysing the Selection of Materials for Knee Implant Femoral Components using the TOPSIS method

Specialists are creating more sophisticated and useful materials daily as technology advances. For orthopaedic implants such as "knee replacements, hip replacements, and orthopaedic accessories", biomaterials are employed to produce prosthetic organs. In patients with severe osteoarthritis (OA) of the knee, "total knee replacement (TKR)" is one of the most successful surgical procedures for pain management and functioning rehabilitation. Humans continue to experience issues with the kneecap, such as aseptic dislocation brought on by excessive wear across articular surfaces, stress-shielding of the bone by prostheses, and soft tissue formation at the junction of implanted bone. due to improper “TKR material selection”. Since selecting the best materials for the femoral component of TKR requires careful consideration, the "technique for order of preference by similarity to ideal solution (TOPSIS)" is used in this research paper. This technique uses an order of preference based on how closely the preferred option is to the ideal solution. The "equal weights method (EWM)" assigns various criteria distinct weights of importance. The rank of alternatives using the TOPSIS method for “Co-Cr-Mo is fourth, Co-Ni-Cr-Mo is third, NiTi SMA is first, Porous NiTi SMA is second, pure Ti is sixth and Ti-5Al-2.5Fe is fifth”. The result indicated that FC material using TKR Nickel Titanium Shape Memory Alloy (NiTi SMA) is at rank 1 with properties such as Tensile Strength 960 MPa, Density 6.45 g/cc, extremely high Corrosion resistance, and exceptionally high Wear resistance.

Association of sagittal alignment of tibial and femoral components with clinical outcome in total knee arthroplasty: A prospective cohort study

BackgroundIn total knee replacement component alignment is a very crucial parameter to achieve better clinical outcomes. Only a few studies exist in the literature on the association between sagittal alignment of components and clinical outcomes. The study aimed to measure the functional outcome and association between the sagittal alignment of total knee replacement components and their clinical outcome. Material & methodsProspectively we collected data of 81 knees (cases) following total knee replacement. The sagittal femoral angle, anterior and posterior tibial slopes were assessed on 2nd postoperative week using a lateral radiograph. Based on these measures 2 groups were made. Group A comprises of the femoral component which was further divided into A1 (41 cases) and A2 (40 cases) based on the component's sagittal femoral angle in flexion or extension.Group B comprises of Tibial component subgrouped based on the degree of Tibal angle as the posterior tibial slope or anterior tibial slopes. The B1 subgroup has posterior tibial slope of more than 5° (23 cases), B2 posterior tibial slope within 5° (53 cases), and B3 anterior tibial slope (5 cases). Preoperative and follow-ups at one month, 6 months, and 3 year; the functional assessment was performed using the American Knee Society score and Oxford knee scores. The duration to raise the leg straight (in days) was also measured. Results52 patients (81 total knee replacement cases) with a mean age of 62.88 ± 8.21 were enrolled. Results showed significant improvement in mean American Knee Society score (preoperative 32.91 ± 2.61 to 86.68 ± 2.52 postoperatively at 3 years; P < 0.001) and mean Oxford knee score (preoperative 34.69 ± 1.06 to 19.20 ± 1.91 postoperatively at 3-years; P < 0.001). The correlation of American Knee Society score between the femoral component angle and tibial component angle suggested that the maximum correlation was between Group A2 (Femoral angle = 91 to 95) and Group B2 (Tibal angle = 86 to 90), with p-value <0.0001. ConclusionsThere is a positive association between the proper sagittal alignment of femoral component and tibial component in total knee replacement with clinical outcome. The functional outcome (in terms of mean American Knee Society score) is better when the femoral component is positioned in extension and the posterior tibial slope of less than 5° is achieved.

CAN SHOE SIZE CORRECTLY PREDICT THE SIZE OF COMPONENTS OF TOTAL KNEE REPLACEMENT PRE-OPERATIVELY

Objective: To ascertain the correlation between shoe size and sizes of femoral and tibial components of total knee replacement preoperatively in patients undergoing total knee arthroplasty. Study design: Prospective cohort study Study settings and duration: This study was conducted at department of orthopedic surgery, Shifa International Hospital, Islamabad from July 2020 – December 2020. Material and methods: Sample size was calculated using WHO calculator and it was 43 patients in total. Patients were approached through non-probability consecutive sampling. Shoe size of patients was measured using a Brannock device. During surgery, Implant model and sizes of the femoral and tibial components implanted during knee replacement were noted. Data was analyzed with the help of SPSS version 24. We applied Pearson’s correlation cofficeint. P value ≤ 0.05 was considered significant. Results: Out of 43, there were 9(20.9%) male and female 34(79.1%). Mean age of patients was 51.7±6.8 (SD). We found good positive correlation between shoe size and tibial component (p=&lt;0.001). Positive co relation was found between femoral component and shoe size (p=0.001). Shoe size predict 72% of Tibial component and 65% femoral component. Conclusion: Shoe size is effective and safe predictors of total knee replacement components pre-operatively. This procedure is more accurate and less labor intensive. Accurate templating result in less surgical duration and provide several benefits to patients and health care providers.

Wear mechanism and debris analysis of PEEK as an alternative to CoCrMo in the femoral component of total knee replacement

The polyetheretherketone (PEEK)-highly cross-linked polyethylene (XLPE), all-polymer knee prosthesis has excellent prospects for replacing the traditional metal/ceramic-polyethylene joint prosthesis, improving the service life of the joint prosthesis and the quality of patients’ life. The long-term wear mechanism of PEEK-XLPE knee joint prosthesis is comprehensively evaluated from wear amount, wear morphology, and wear debris compared to that of CoCrMo-XLPE joint prosthesis. After 5 million cycles of in vitro wear, the wear loss of XLPE in PEEK-XLPE (30.9±3.2 mg) is lower than that of XLPE in CoCrMo-XLPE (32.1±3.1 mg). Compared to the XLPE in CoCrMo-XLPE, the plastic deformation of XLPE in PEEK-XLPE is more severe in the early stage, and the adhesive peeling and adhesion are lighter in the later stage. The size distribution of XLPE wear debris in PEEK-XLPE is relatively dispersed, which in CoCrMo-XLPE is relatively concentrated. Wear debris is mainly flake and block debris, and the wear mechanism of XLPE was abrasive wear. The wear volume per unit area of PEEK femoral condyle (10.45×105 µm3/mm2) is higher than that of CoCrMo (8.32×105 µm3/mm2). The PEEK surface is mainly furrows and adhesions, while the CoCrMo surface is mainly furrows and corrosion spots. The PEEK wear debris is mainly in flakes and blocks, and the CoCrMo wear debris is mainly in the shape of rods and blocks. The wear mechanism of PEEK is abrasive wear and adhesion, and that of CoCrMo is abrasive wear and corrosion.

Multiple-Criteria Decision-Making and Sensitivity Analysis for Selection of Materials for Knee Implant Femoral Component.

Total knee replacement (TKR) is a remarkable achievement in biomedical science that enhances human life. However, human beings still suffer from knee-joint-related problems such as aseptic loosening caused by excessive wear between articular surfaces, stress-shielding of the bone by prosthesis, and soft tissue development in the interface of bone and implant due to inappropriate selection of TKR material. The choice of most suitable materials for the femoral component of TKR is a critical decision; therefore, in this research paper, a hybrid multiple-criteria decision-making (MCDM) tactic is applied using the degree of membership (DoM) technique with a varied system, using the weighted sum method (WSM), the weighted product method (WPM), the weighted aggregated sum product assessment method (WASPAS), an evaluation based on distance from average solution (EDAS), and a technique for order of preference by similarity to ideal solution (TOPSIS). The weights of importance are assigned to different criteria by the equal weights method (EWM). Furthermore, sensitivity analysis is conducted to check the solidity of the projected tactic. The weights of importance are varied using the entropy weights technique (EWT) and the standard deviation method (SDM). The projected hybrid MCDM methodology is simple, reliable and valuable for a conflicting decision-making environment.

Plastics in Total Knee Replacement: Processing to Performance.

Polyethylene (PE) is the key component of total knee replacement (TKR). The wear of polyethylene, a common cause of revision surgeries, depends on multiple factors. The mechanical properties, wear characteristics, and oxidative resistance of PE can be manipulated by the techniques of processing, sterilization, and packaging methods. This article describes the making of conventional and cross-linked poly, packaging, sterilization, processing techniques, and a summary of commercially available plastics and their rationale in TKR including the latest advances.

Safety of apixaban in Indian patients undergoing elective total knee replacement or total hip replacement surgery: A multi-center, phase-IV study.

Background:Venous thromboembolism is a significant source of morbidity and mortality following total hip replacement and total knee replacement. Apixaban has been proven to be efficacious without increased risk of bleeding in phase-III trials in patients undergoing total knee replacement and total hip replacement. Due to paucity of data on safety of apixaban in Indian patients, this phase-IV study was conducted to evaluate safety of apixaban in patients undergoing total knee replacement and total hip replacement.Methods:In this non-comparative phase-IV clinical trial, patients undergoing elective total knee replacement or total hip replacement surgery, or a revision of at least one component of total knee replacement or total hip replacement, were enrolled. The eligible patients were given the approved dosage of apixaban 12 to 24 h after completing the skin wound closure. The primary safety outcome was the composite of the International Society on Thrombosis and Haemostasis–defined major bleeding and clinically relevant non-major bleeding events at the end of the treatment. The secondary efficacy endpoint was the composite of venous thromboembolism/all-cause death at the end of the treatment.Results:A total of 498 patients received apixaban prophylaxis therapy. Six (1.2%) bleeding adverse events were observed during the treatment period. Only one bleeding event was adjudicated as an International Society on Thrombosis and Haemostasis–defined clinically relevant non-major bleeding event (moderate severity). There were no fatal bleeding events and no deaths following the treatment. One venous thromboembolism event, that is, symptomatic distal left leg DVT, was reported in a total knee replacement patient and was adjudicated during the treatment period.Conclusion:Apixaban demonstrated a favorable safety profile for venous thromboembolism prevention in Indian patients undergoing total knee replacement or total hip replacement.

FUNCTIONAL AND RADIOLOGICAL OUTCOMES OF THREE TIBIAL COMPONENT FIXATION TECHNIQUES: RESULTS OF A PROSPECTIVE RANDOMISED CONTROLLED TRIAL

Introduction: Cemented and uncemented fixation of tibial component in total knee replacement (TKR) are well described. Each method has perceived advantages and inherent limitations. However, there is paucity of studies in current literature performing comparative evaluation of these methods.

‘Rotational alignment on patients’ clinical outcome of total knee arthroplasty: Distal femur axillary X-ray view to qualify rotation of the femoral component

“Background: Rotation of the femoral component in total knee replacement (TKR) is very important for good long-term results. Malrotation of the femoral component usually requires subsequent reimplantation. We performed X-ray projections of the knee at 90° to determine proper rotation of the femoral component without use of computed tomography.

Fracture of the Femoral Component in TKR – A Case Report

Femoral component fracture in total knee replacement (TKR) is a rare complication. In the majority of case reports, stress fractures of the femoral component have predominantly affected the medial condyle, following uncemented implantation of fixed-bearing knees. We report the case of fracture of the lateral condyle of a cemented fixed TKR due to bad cementing technique.

Current review of surgical management options for rotational alignment of the femoral and tibial component in total knee replacement

Rotational malalignment complication following TKA, is common but can be avoided with proper surgical technique. This paper reviews the literature regarding rotational alignment during TKA, femoral and tibial rotation, and highlights the techniques prior in obtaining proper rotational positioning, nevertheless correct positioning in all three planes is important. Proper femoral component positioning in the axial plane is done using as landmarks the posterior condylar line (PCL), surgical transepicondylar axis (sTEA), anatomical transepicondylar axis and the trochlear anteroposterior (AP) axis. The paper describes the angular relationships between these landmarks and the distal femur. Axial tibial positioning is done when using intraarticular landmarks, the combination of more than one landmark could be a solution for solving this problem. The consensus is that femoral component should be positioned according to TEA but the interobserver variability of this land mark is very high. The rotation of the tibial component remains an open subject, most studies suggesting a point between half of the distance of patellar ligament and 1/3 of the internal tuberosity as optimal landmark.

Agreement in component size between preoperative measurement, navigation and final implant in total knee replacement

SummaryBackgroundOne of the possible causes of dissatisfaction reported by many patients after total knee replacement (TKR) is the lack of agreement between component size and bone structure. To avoid this complication and facilitate the procedure, preoperative planning with digitized templates is recommended. Surgical navigation indicates the best position and the most adequate size of arthroplasty and may therefore replace preoperative radiographic measurement. The objective of the study was to check agreement between the sizes of TKR components measured before surgery with digitized templates, the size recommended by the navigation and sizes actually implanted.MethodsIn 103 patients scheduled for TKR, preoperative full-limb radiography was performed to measure the mechanical and anatomical axes of the limb, femur and tibia. The most adequate size of the femoral and tibial components was planned by superimposing digitized templates. The size recommended in navigation and the size of the finally implanted components were also recorded.ResultsA high level of agreement was found between the sizes of femoral and tibial components measured by X-rays and in navigation (0.750 and 0.772, respectively) (intraclass correlation and Cronbach's alpha). Agreement between the sizes recommended by X-rays and navigation and those finally implanted was 0.886 for the femur and 0.891 for the tibia. Agreement levels were not different in cases with prior deformities of limb axis.ConclusionsThe high level of agreement found in component sizes between radiographic measurement with digitized templates and navigation suggests that preoperative X-ray measurement is not needed when navigation is used for placement of implants during TKR.The translational potential of this articleComputer-assisted surgery may avoid preoperative measurement with templates in TKR.

All-Polyethylene Tibial Components in Total Knee Replacement: Early Failures.

In total primary knee replacement surgery, the use of all-polyethylene tibial (APT) components has many advantages, including no backside wear and no linear dissociation. In addition, the greater polyethylene thickness permits more conservative bone resection compared with that for metal-backed components, with a lower unit cost and similar functional results. Thus, the use of an APT in primary total knee arthroplasty remains an attractive option. This is a review of 158 patients who underwent primary knee replacement using APT components from a single manufacturer. Data collection included age, American Society of Anesthesiology physical status classification, body mass index (BMI), type of deformity, the presence of diabetes mellitus, rate of revision, and characteristics associated with early failure of the components. Average follow-up time was 40 months. The revision rate for any reason was 5.6%, and the average BMI in revision cases was 37.6. Patients with a higher BMI (≥ 37.6) were significantly more likely to require revision surgery than patients with a lower BMI (p = 0.04). In our sample, high BMI was a contributing factor for early failures in total knee replacements using an APT component. Generally, polyethylene tibial components used for primary knee replacements are safe and effective, with good outcomes and subsequent lower costs to the health care system.

Wear and Friction of UHMWPE-on-PEEK OPTIMA™

PEEK-OPTIMA™ is being considered as an alternative bearing material to cobalt chrome in the femoral component of total knee replacement to provide a metal-free implant. The aim of this study was to investigate the influence of lubricant temperature (standard rig running and elevated temperature (~36 °C)) on the wear of a UHMWPE-on-PEEK OPTIMA™ bearing couple using different lubricant protein concentrations (0%, 2%, 5%, 25% and 90% bovine serum) in a simple geometry pin-on-plate configuration. Friction was also investigated under a single temperature condition for different lubricant protein concentrations. The studies were repeated for UHMWPE-on-cobalt chrome in order to compare relationships with temperature (wear only) and lubricant protein concentration (wear and friction).In low lubricant protein concentrations (≤ 5%) there was no influence of temperature on the wear factors of UHMWPE-on-PEEK. With 25% bovine serum, the wear factor of UHMWPE-on-PEEK reduced by half at elevated temperature. When tested in high protein concentration (90% serum), there was no influence of temperature on the wear factor of UHMWPE-on-PEEK. These temperature dependencies were not the same for UHMWPE-on-cobalt chrome.For both material combinations, there was a trend of decreasing friction with increasing protein concentration once protein was present in the lubricant.This study has shown the importance of the selection of appropriate test conditions when investigating the wear and friction of different materials, in order to minimise test artefacts such as polymer transfer, and protein precipitation and deposition.

Validation of model-predicted tibial tray-synthetic bone relative motion in cementless total knee replacement during activities of daily living

As fixation of cementless total knee replacement components during the first 4–6 weeks after surgery is crucial to establish bony ingrowth into the porous surface, several studies have quantified implant-bone micromotion. Relative motion between the tray and bone can be measured in vitro, but the full micromotion contour map cannot typically be accessed experimentally. Finite element models have been employed to estimate the full micromotion map, but have not been directly validated over a range of loading conditions. The goal of this study was to develop and validate computational models for the prediction of tray-bone micromotion under simulated activities of daily living. Gait, stair descent and deep knee bend were experimentally evaluated on four samples of a cementless tibial tray implanted into proximal tibial Sawbones™ constructs. Measurements of the relative motion between the tray and the anterior cortical shell were collected with digital image correlation and used to validate a finite element model that replicated the experiment. Additionally, a probabilistic analysis was performed to account for experimental uncertainty and determine model sensitivity to alignment and frictional parameters. The finite element models were able to distinguish between activities and capture the experimental trends. Best-matching simulations from the probabilistic analysis matched measured displacement with an average root mean square (RMS) difference of 14.3 µm and Pearson-product correlation of 0.93, while the mean model presented an average RMS difference of 27.1 µm and a correlation of 0.8. Maximum deviations from average experimental measurements were 40.5 and 87.1 µm for the best-matching and average simulations, respectively. The computational pipeline developed in this study can facilitate and enhance pre-clinical assessment of novel implant components.

Electromyography-Driven Forward Dynamics Simulation to Estimate In Vivo Joint Contact Forces During Normal, Smooth, and Bouncy Gaits.

Computational models that predict in vivo joint loading and muscle forces can potentially enhance and augment our knowledge of both typical and pathological gaits. To adopt such models into clinical applications, studies validating modeling predictions are essential. This study created a full-body musculoskeletal model using data from the "Sixth Grand Challenge Competition to Predict in vivo Knee Loads." This model incorporates subject-specific geometries of the right leg in order to concurrently predict knee contact forces, ligament forces, muscle forces, and ground contact forces. The objectives of this paper are twofold: (1) to describe an electromyography (EMG)-driven modeling methodology to predict knee contact forces and (2) to validate model predictions by evaluating the model predictions against known values for a patient with an instrumented total knee replacement (TKR) for three distinctly different gait styles (normal, smooth, and bouncy gaits). The model integrates a subject-specific knee model onto a previously validated generic full-body musculoskeletal model. The combined model included six degrees-of-freedom (6DOF) patellofemoral and tibiofemoral joints, ligament forces, and deformable contact forces with viscous damping. The foot/shoe/floor interactions were modeled by incorporating shoe geometries to the feet. Contact between shoe segments and the floor surface was used to constrain the shoe segments. A novel EMG-driven feedforward with feedback trim motor control strategy was used to concurrently estimate muscle forces and knee contact forces from standard motion capture data collected on the individual subject. The predicted medial, lateral, and total tibiofemoral forces represented the overall measured magnitude and temporal patterns with good root-mean-squared errors (RMSEs) and Pearson's correlation (p2). The model accuracy was high: medial, lateral, and total tibiofemoral contact force RMSEs = 0.15, 0.14, 0.21 body weight (BW), and (0.92 < p2 < 0.96) for normal gait; RMSEs = 0.18 BW, 0.21 BW, 0.29 BW, and (0.81 < p2 < 0.93) for smooth gait; and RMSEs = 0.21 BW, 0.22 BW, 0.33 BW, and (0.86 < p2 < 0.95) for bouncy gait, respectively. Overall, the model captured the general shape, magnitude, and temporal patterns of the contact force profiles accurately. Potential applications of this proposed model include predictive biomechanics simulations, design of TKR components, soft tissue balancing, and surgical simulation.

Evaluation of the Tibiofemoral Contact Characteristics of a Customized Surface-Guided Knee Implant

A surface-guided total knee replacement (TKR) aims to achieve close to normal kinematics through specially shaped tibiofemoral articulating surfaces. The resulting geometry of the TKR components affects the tibiofemoral contact mechanics. Therefore, evaluation of the contact characteristics of the implant is critical, as the tibiofemoral contact stress influences the short-term and long-term performance and durability of the implants. In this study, the contact behavior at the tibiofemoral articulating interface for a customized surface-guided TKR was studied. The contact area and mean contact stress at specific flexion angles were measured mechanically by pressure sensitive films to validate the outcomes from finite element analysis (FEA) under similar load conditions. Two activities of daily living were studied; lunging and squatting. As expected, FEA predicted larger contact areas at various flexion angles due to the limited sensitivity range of the pressure sensitive films. During lunging and squatting, the contact area increased as the flexion angle reached 90°, and decreased as the knee was flexed to higher angles. The mean contact pressure was less than 10 MPa at 120 degrees of flexion under squatting load. The outcomes revealed that a high range of motion can be achieved, while the mean contact pressure remains below the material limits of the tibial polyethylene insert.

Total knee replacement modifies the preoperative tibial torsion angle-similar results between computer-assisted and standard technique.

Malpositioning of the components in total knee replacement (TKR) can result in failure or deficient outcomes of the surgical procedure. In the tibial segment, the rotational position of the tray should reproduce the mechanical axis without modifying physiological tibial torsion. A randomised, prospective study was made of 74 patients subjected TKR involving the standard technique (38 cases) and navigation surgery (36 cases). A computed tomography study of the knee and ankle was made before the operation and after arthroplasty implantation, in order to identify the position of the prosthetic tibial tray in the transverse axis and the tibial torsion angle. The rotation of the tibial tray changed from its preoperative to postoperative range, but no significant differences were found between the navigated and the standard groups. The presence of preoperative deformities in the frontal plane did not modify the changes in the rotation of the tibial component. The mean preoperative tibial torsion angle was 17.76º (SD =10.15) of external rotation, with no significant differences in relation to the previous frontal deformity. After TKR, the tibial torsion angle was 15.36º (SD =7.16) (P=0.021). There were no differences in final tibial torsion between the knees operated upon with the standard instruments and those subjected to computer-assisted surgery (CAS; P=0.157). TKR surgery modifies preoperative tibial torsion. Neither mechanical instrumentation nor navigation surgery precisely reproduces the rotational axis of the leg.

Precision CNC Machining of Femoral Component of Knee Implant: A Case Study

The design and manufacturing of medical implants constitutes an active and highly important field of research, both from a medical and an engineering point of view. From an engineering aspect, the machining of implants is undoubtedly challenging due to the complex shape of the implants and the associated restrictive geometrical and dimensional requirements. Furthermore, it is crucial to ensure that the surface integrity of the implant is not severely affected, in order for the implant to be durable and wear resistant. In the present work, the methodology of designing and machining the femoral component of total knee replacement using a 3-axis Computer Numerical Control (CNC) machine is presented, and then, the results of the machining process, as well as the evaluation of implant surface quality are discussed in detail. At first, a preliminary design of the components of the knee implant is performed and the planning for the production of the femoral component is implemented in Computed Aided Manufacturing (CAM) software. Then, three femoral components are machined under different process conditions and the surface quality is evaluated in terms of surface roughness. Analysis of the results indicated the appropriate process conditions for each part of the implant surface and led to the determination of optimum machining strategy for the finishing stage.